1. Field
Exemplary embodiment of the present invention relate to a light scanning unit and an image forming apparatus including the same, and more particularly, to a light scanning unit and an image forming apparatus including the same, the light scanning unit improving a problem of multiple reflection of light beams in an image forming optical system.
2. Description of the Related Art
Electrophotographic image forming apparatuses such as laser printers, digital copiers, multifunctional printers (MFP) have a configuration in which an electrostatic latent image is formed by scanning light to a photosensitive medium by using a light scanning unit, the formed electrostatic latent image is transformed to a developed image by using a developer such as a toner, and the developed image is transferred onto a printing medium.
A light scanning unit employed by an image forming apparatus scans light beams to a main scanning direction by using an optical deflector such as a polygonal rotating mirror and a vibrating mirror, the apparatus including an incident optical system for incidence of the light beams to the optical deflector and an image forming optical system forming an image on a scanning target surface, that is, a photosensitive medium using the light beams scanned while being deflected by the optical deflector. However, when an optical axis of the incident optical system in a sub-scanning direction is identical to that of the image forming optical system in a sub-scanning direction, multiple reflected light beams occurring between an incident surface and an emitting surface of a scanning optical element (an element featuring a “fθ characteristic”) of the image forming optical system are scanned to an effective image area of the scanning target surface, leading to deteriorated uniformity in density of an image. Conventionally, in an attempt to address such problems, reflection occurring between an incident surface and an emitting surface of a scanning optical element of an image forming optical system may be maximally suppressed by forming a non-reflective coating layer on the surfaces, or an optical axis of the scanning optical element may be separately disposed from an optical axis of an incident optical system to be eccentric in such a way that multiple reflected light beams avoid an effective image area of normal scanning light beams.